Sanding and polishing machine



Jam 19, 1932- R. CARTER SANDING AND POLISHING MACHINE Filed April 28, 1950 2 Sheets-Sheet SQ I |NvENToR` ATTORNEY.

Jan. 19, 1932. R. l.. CARTER 1 SANDING AND POLISHING MACHINE Filed April 28, 195o 2 sheets-sheen 2 ATTORNEY.`

I I 15.71111. Arlllll-IIIIIHI Patented Jan. 19, 1932 UNITED STATES PATENT Y OFFICE RAY L. CARTER, OF PHOENIX, NEW YORK, ASSIGNOR T THE STANLEY WORKS, 0F NEW BRITAIN, CONNECTICUT, A CORPORATION OF CONNECTICUT SAN DING AND POLISHING MACHINE Application sled Aprn 2s,

This invention relates to a portable motor driven abrading machine, of the belt type, particularly adapted for sanding and polishing floors and other flat wooden surfaces, and has for its object to provide novel and simple construction whereby the belt may be automatically released from contact with the floor when the working pressure is relaxed, and whereby its forward end is supported in a '1" manner to render it adjustable within a certain range, and is provided with simple means v for refining the adjustment that regulates the depth of the abrading cuts, and enable the operator to erform uniform surfacing andv polishing. nd a further object is to generally improve, simplify, and render more ecient and reliable abrading and polishing devices of the class.

I attain these objects by the means set forth in the detailed description which follows, and as illustrated by the accompanying drawings, in which- Figure 1 is a. rear side elevation of the complete machine, the belt being depressed to the abrading position. Fig. 2 is a front side elevation of the same. Fig. 3 is a top plan View. Fig. 4 is a. vertical cross-section, taken on line 4-4 of Fig. 3. Fig. 5 is a front end elevation. Fig. 6 is a detached plan view of the yoke that supports the front pulley and also the belt reinforcing shoe. Fig. 7 is a vertical cross-section, taken on line 7-7 of Fig. 2, showing the means for expanding and contracting the grill bracket.

In the drawings, 2 represents an elongated frame having an enlarged hollow head 2 at one end, tocontain the transmission mechanism, and a forwardly declining portion 2a,

upon which is mounted an electric motor 3, "l whose rear or work performing end abuts said head. The frame portion 2a is preferably closed at its rear side by a wall 2b, its front side 2c being normally open for affording access to, or inspection of, the ab-rading belt 4, which is supported and driven by pulleys 4-A4a, preferably of different diameters, as shown. The shaft 3 of the motor extends into the head 2 and is fitted with a bevel pinion 3a, that drives a. bevel gear 3b, which is mounted upon one end of a shaft 5 that eX- 1930. Serial No. 447,975.

tends transversely within the head. Upon the opposite end of shaft 5 is mounted a spurgear 5 that drives an idler gear 6, the latter being mountedupon a short shaft 6 which is preferably threaded into a cap 2d, that closes the rear side of the head, as shown in Figs. 1 and 4. The gear 6 drives a gear 7, which is journaled upon a short shaft 7 that is also threaded into said cap. The gear 7 is formed with a threaded hub 7a that screws into the corresponding end of, and drives the pulley 4. The opposite end of pulley 4 is rotatably supported by a grille bracket 8, which is formed with a gudgeon 8 that enters the bore of the pulley (see Fig. 4). The forward end of the bracket 8 is rigidly secured to a. boss or stud 9 that projects laterally from a cylinder 9, which is disposed longitudinally between the top and bottom runs of the belt 4, said cylinder preferably being cast with and supported by the wall 2b. The several gears and shafts of the transmission train that connect the motor with the pulley 4 are preferably mounted in ball-bearings, as best seen in Fig. 4. The smaller pulley 4a is preferably hollow and is supported by a yoke shaped member 10, which supports gudgeons 10 that extend into the bore at the opposite ends of the pulley, said yoke has a rearwardly extending stem 10a and a reduced portion 105, which is reciprocable plunger-like in the cylinder 9, the latter being counter-bored at 9a, to house a compression spring 9b, which tends to hold the yoke and pulley 4a extended forwardly and affords the requisite abrading ten sion for the belt 4. The pulley 4a may be moved towards the pulley 4 for slackening the belt, either for adjustment or removal thereof, by means of a transverse rod 13, which extends through the wall 2b and is formedwith an eccentric portion 13', that is disposed in a slotted socket 12 formed in the enlarged portion of stem 10a. rlhe outer end of rod 13 is fitted with a handle 13a, which when rocked downwardly (see Fig. 1) thrusts the stem rearwardly against the tension of spring 9b, and shortens the normal distance between the pulleys 44a. The belt 4 may then be removed by moving it bodily through the open side 2o of the frame.

. the rod. The rod 16 is arranged to slide a.-

`tions 16a, which are engaged by adjust The whole machine is supported by longitudinal parallel runners or skids le that eX- tends substantially the full length ot the frame 2, and are spaced to allow loose play for the belt 4, to enable the latter to abradethe intervening exposed surface oi a door, or the like. The rear ends of the runners are formed with angular lugs 1d that are secured to the lower rear corners of the head 2, by screws llc. T ie lugs lil are preferably so formed as to elevate the head 2 oi the machine from the plane ot a floor, while the 'forward end of a traine is tree from the runners and is movable in vertical plane independentlyT of the runners. lly this arrangement, the belt 4 is always disposed a slight declination relatively to the hea( and only the. forward half of 'the belt may contact with the surfaces to be abraded when the corresponding end of the 'frame is depressed. This greatly reduces 'the tractive area and resistance, obviates wear and tear of the belt Ll and enables the motor to mamtain a relatively high speed during .the abrading operations, which is very desirable. The forward ends of the runners 14 are tied to each other by a transverse bracket or head 15, whose opposite ends are formed with arms 15-15c that rise from a relatively low web 15?) that forms one margin of a transverse opening 4m through which the pulley la extends during the abrading operations. The arms l515a are perforated horizon` tally to receive an adjusting rod or sha w having at one end a hand-knob for rotatin ally in the arm 15', while the opposite end or said rod is reduced and threaded at 1li to engage threads of the perforation in arm lloc', and between the said arms the rod lt; formed with similar spaced conical cam porscrews or like members l? that are ri'gi secured to and depend from the 'forward e of the frame deck 2e, and ailord positive stoy` to limit or control the downward movern of the forward end of the frame and belt c therefore may accurately dene the depth f the abrading cuts. The bracket l5 is titte lnedially with an upright post 18, having reduced portion 18 that extends through an opening in the deck 2c and is provided with a removable head 18a to prevent detachment of the parts. The post 1S is surrounded by coil compression spring 18?), whose top end engages the underside of and supports the deck and tends to lift and resiliently hold the belt 4 clear of the floor, so that the motor 3 may be started, or allowed to continue in motion, without danger of the belt making accidental contact with the worlr.

Adjacent the pulley 4a is disposed a reiir forcing shoe 19, which is mounted directly above and in intimate contact with the lower run of the belt 4, and forms the rear margin ot the opening 4m. This shoe extends rearwardly a considerable distance, has substantially the saine breadth as the belt, and when the belt is tightened, exerts suitable rigidity and pressure over a relatively large plane surface, which comprises virtually the effective abrading area. The present shoe is preferably pivoted intermediate its ends by a bolt 19', that passes through threaded arms l0@ of the yoke 10 and also extends through lugs 19a ol the shoe (see Figs. 3 and By this arrangement. the shoe may rock or teeter slightly ,in a vertical plane which enables the belt to yield upwardly slightly when it encounters ridges or bumps, thereby lessening the resistance due to the abrupt rise in the surface of the work, relieving the harsh ness of the abrading and avoiding extraV strain that may cause undue wear and tear or the belt.

Vllhe bracket 8, in addition to supporting one end of the pulley ll, is also employed -for adjusting the axis of said pulley, relatively to that of the pulley 4a, to prevent the accidental shedding ot the belt. To this end, the central web of the bracket is formed with a gap 8a, the medial portion ot which is circular, and receives the small end oi: a conical portion 8o or a rod 8c, which extends through the wall 2o, in which the rod is preferably threaded. rlhe outer end of rod 8c is formed with a linurled hand-knob 8d tor rotating the rod and moving the cone 8b axially towards and from the opening Se, for expanding and contracting the bracket in a transverse direction (see Figs. 2 and 7 F or this purpose, the lateral margins, as 8c, directly opposite the opening 8a, are formed relatively thin possess suflieient llexibility to eiliect the contraction and expansion of 'the bracket by the opposing movements of 'the rod 8c. For er amp-le, when the cone 8l) is driven into opening 8a, it enlarges the gap and lieXes the portions 86 in the direction to lengthen the distance between the axis oi' pulley 4 and that of the stud 9. This moves the end of the pulley ll" away from the pulley 40;. When 'the rod 8c is rotated in the opposite direction, the cone 8b is withdrawn from gap 8o, and the resilience of the portions 8e will then expand the bracket (see dotted lines lig. 7), and correspondingly shorten the distance between pulley 4 and pulley 4a. By this means, any slight discrepancy in the parallelism of the axes of the two pulleys may be rectified and cause the belt to travel truly.

To make the machine ready for an abrading job, the operator adjusts rod 16 and also the screws 17 so as to accurately define the depth of the particular abrading work. The screws 17 are then locked by nuts 17. Dur- -ing the interval between the said adjustment and the start of the work, the forward end of the frame 2a is elevated and the screws 17 disengaged, by the spring 18. To begin the work, the operator grasps a handle carried lby the head 2 with one han-d and a knob mounted on the deck 2e with the other hand, depresses the forwardend of the frame to the extent allowed by the screws 17, and then propels the machine over the rough and unpolished work while maintaining the pressure upon the knob.v The runners 14 may comprise spring steel, and being relatively long and narrow have suiiicient dexibility to allow the forward end of the frame to be lowered to the abrading plane by relatively slight pressure. rlhe operator may increase or vary this pressure to suit the conditions of the work, as well as to accelerate the abrading. By providing the relatively narrow, smooth and springy runners le, the propulsion of the machine requires but little physical eort and greatly facilitates the maneuvering and steering of the device.

in the present machine, the lower run of the belt d travels preferablyforwardly in the direction of the propulsion of the machine. This greatly facilitates ed'ective and smooth abrading in a true plane, and obviates a natural tendency of the machine to climb .like a tractor over humps or other raised portions of the work without eneectively abrading said portions unless the operation is repeated.

Having thus described my invention, what l cla-im, is-

l. A portable abrading machine including an elongated frame', a pair of spaced parallel runners pivoted to the rear end of the frame to sustain the weight of the machine and enable the forward end of the frame to be moved vertically, pulleys and an Yabrading 'belt driven thereby disposed in the frame, means to drive said pulleys so that the lower run of the belt moves forwardly, compression means to move the pulleys away from each other to tension the belt, cam means to move said pulleys towards each other to enable the belt to be removed, and means movable transversely of the frame to adjust one end of one of the pulleys to establish parallelism of the axes of said pulleys.,

2. lln an abrading machine, an elongated frame, a pair of spaced runners pivoted to the rear end of the frame and extending forwardly to its front end, spaced pulleys disposed in the frame, a yoke to support the orward pulley, a grillesupport for one end of the rearmost pulley, means to expand and contract said support to establish parallelism of the axes of said pulleys, an abrading belt movable over said pulleys adapted by the depression of the front end of the frame to abrade the portion of a surface lying between said runners, a bracket to connect the forward ends of the runners, and compression means carried by the last named bracket to normally hold the belt out of contact with said surface.

3. A portable machine for abrading floors and the like, including an elongated frame, a pair of pulleys, an abrading belt carried by the pulleys, an electric motor to ^drive said belt, parallel runners beneath the frame to enable the machine to be propelled over ther door, said runners being pivoted to the rearM end of the frame to enable the front end of the frame to be moved in a vertical plane independently oflsaid runners, said runners being spaced to enable the bolt to abrade the portion of the licor lying betweenfthe runners when said front end is depressed, compression means to elevate the front end of the frame to render the belt inoperative when the depressing force is relaxed, and a shoe pivoted between the runners and in intimate contact with the lower run of the belt adapted to teeter in a vertical plane when the belt encounters humps that rise above thenormal plane of the work.

fl. ln an abrading machine, an elongated frame, a pair of parallel runners pivoted to the rear end of the frame and extending forwardly the length of the frame, but being free from the front end thereof, 4a pulley disposed in the rear end of the frame, a grille member supporting one end of said pulley, a pulley disposed inthe opposite end of 'the frame, a yoke tosupport said pulley, means to expand and contract the grille member to establish the parallelism of the axes of said pulleys, an abrading belt .movable over said pulleys and traversing the space between said runners, means disposed at the forward end of the Yframe to normally elevate said belt above a-surface to be abraded, means to deline the depth of the abrading when the forward end of the frame is depressed, and means to drive said pulleys and i belt.`

5. A portable abrading machine having in combination with an elongated frame, a pair of pulleys, an abrading belt carried thereby, and a motor to drive said pulleys, a pair of parallel runners to enable the machine to be moved frictionally over a surface to be abracled, said runners being pivoted to the rear end of the frame and spaced to enable the belt to abrade a portion of the surface lying therebetween, compression means carried by the forward ends of the runners to normally elevate the belt above the abrading nlane, the forward end of the frame adapted to be depressed by the operator to effect the abrading, and a shoe pivoted in the forward end of said frame to tension said belt, said shoe adapted to teeter in a vertical plane when the belt encounters humps or ridges on theI surface of the work. f

6. An abrading machine having in' combination with an elongated frame, spaced parallel runners to normally support the frame above a surface to be abraded, rollers journaled in the forward and rear ends of the.

llo

4 esame? frame, an abi'ading belt carr'ed by said rollend ot the frame, a second pulley mounted ers, means to drive said rollers bracset in the rear of the trame having one end 3011i'- said runnaled in the latter, a grille member connect- 5 mounted upon the forward ends of ners, compression means to support the ward end of the frame and normally the belt above the plane .of said sur ace, a slice disposed between the top and bottom runs oi'A the belt and tending to depress a. por tion of said bottom run, means to pivotally support said shoe to enable it to teeter when the belt encounters humps or undulations on said surface, and complementary adjusting means carried by the 'forward end of the 'frame and said bracket to deiine the depth of the abrasive cuts when said end is depressed. 7. An abrading nicliine comprising an elongated frame having an enlarged hollow head at its rear end, a pulley journaled in said head, a pulley liournaled near the Jfoinv'ard end of the trame, en abrading belt supported and driven by said pulleys, an electric motor carried by the frame l a train of gears housed by the head., or driving said pulleys, spaced flexible runners disposed beneath and extending substantially 'the length of the frame, the rear ends of said runners being secured to the head, the forward ends thereof being tied to each other by a transverse bracket, compression means carried by said bracket to normally elevate said belt above the plane of the work, means to li mit the upward movement of the frame, and ineans carried by said bracket to gage the downward movement of said end to denne the depth of the abrading when said end is depressed to bring the belt into contact with the work.

8. A portable abrading machine including a frame, a pulley mounted in the forward end of the frame, a second pulley mounted in the rear of the frame having one end journaled in the latter, flexible means carried by the frame for movably mounting the opposite end of the second pulley, an abrading belt carried by said pulleys, means for 'flexing said flexible connecting means to adjust one end of said second pulley to establish parallelism of the axes of said pulleys, and means for actuating said pulleys and belt.

9. A portable abrading machine including aframe, a pulley mounted in the lor-ward end of the frame, a second pulley mounted in the rear of the frame having one end journaled in the latter, a grille member connecting the lopposite end of the second named pulley to the frame having flexible connecting portions and a pair of spaced opposed substantially rigid members., an abrading belt carried by said pulleys, means movable between saidrigid members for flexing the grille member whereby to adjust one end of the second named pulley to establish parallelism of the axes of said pulleys, and means for actuating the pulleys and belt. v

10. A portable abrading machine includ ing a frame, a pulley mounted in the forward ing the opposite end ot the same named pulley to the frame having flexible connecting portions and a .pair of spaced opposed substan tially rigid members, an abrading belt earried by said pulleys, wedge-shaped means movable between said rigid members for flexing the grille member whereby to adjust one end of the second named pulley to establish parallelism of the axes of said pulleys, and 4 means for actuating the pulleys and belt.

ll. A portable abrading machine, including a, frame, a pair of spaced pulleys carried by the frame, an abrading belt supported and driven by said pulleys, means carried by the .frame for driving said pulleys, a movable bracket carried by the frame, means carried by the bracket to normally elevate said belt above the plane of the work, means to limit the upward movement of the frame, and transversely movable substantially coneshaped means carried by the bracket to gage the downward movement of the 'frame to define the depth of the abrading when said frame is depressed to bring the belt into contact with the work.

12. A portable abrading machine including a frame, a pair of spaced pulleys carried by the frame, an abrading belt :supported and driven by said pulleys, means carried by the frame for driving said pulleys, a movable bracket carried by the frame, means carried by the bracket to normally elevate said belt above the plane of the work, means to limit the upward movement of the frame, transversely movable substantially cone-shaped means carried by the b/racket to gage the` downward movement ,of the frame to define the depth of 4the abra/ding when said frame is depressed to brind the belt into Contact with the work, and a shoe pivoted to said trame and in intimate bontact with the lower run of the belt adapted to teeter in a vertical plane when the belt encounters bumps that rise above the normal planeet the/work.

13. A portable abrading machine includ ing an elongated frame, a pair of spaced runners pivoted to the rear end of the frame and sustaining the weight of the machine while the forward end of the frame is 'free to move yertically, an abrading mechanism comprising spaced pulleys and a sanded belt, a flexible bearing support for one end of one of the pulleys, means to drive said pulleys, compres sion means to move said pulleys away from each other to tension the belt, means movable transversely of the frameand through said flexible bearing to adjust one end of one of .the pulleys t0 establish the parallelism of the axes of the pulleys, and compression means to lift and render the belt inoperative.

In testimonywhereof I affix my signature.

RAY L. CARTER. 

